const arr = [1, 2, 3, 4, 5, 6];
// let ret = 0;
// for (let num of arr) {
//     ret += num;
// }
// console.log(ret);

console.log(arr.reduce((total, currentValue) => {
    return total + currentValue;
}, 0))

// 参考：https://juejin.cn/post/6844904063729926152